In this presentation, I will use pyruvic acid as a case study to demonstrate the ability of organic molecules to initial radical chemistry in aqueous atmospheric particles. The photochemistry of pyruvic acid in the gas phase proceeds on different potential energy surfaces than in aqueous solution, resulting in vastly different mechanisms for the chemistry between the two phases. While the gas phase reactions generally decrease the complexity of products, the aqueous chemistry can create higher molecular weight compounds through a radical mechanism. Further, pyruvic acid photochemistry in the aqueous phase can polymerize MVK in a similar manner to OH radical, a reaction that yields surface-active products. This result indicates that organic keto-acids could be an important source of radicals in the atmosphere in terms of initiating polymerization and the formation of products that partition to the air-water interface. I will also discuss the photochemistry of nebulized pyruvic in an environmental simulation chamber (CESAM) to highlight the effect of pressure, oxygen, and relative humidity on the radical chemistry discussed above.

Multiphase photochemistry of pyruvic acid and surface active products

251st National Meeting (2016)

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